"I don't believe Mark Clattenburg would make comments like that," Ferguson told reporters. "I refuse to believe it. I think it's unthinkable in the modern climate. I just don't believe it. It's as simple as that.

Chelsea has made an official complaint to the Football Association over the incident, while the Metropolitan Police have stated that they are working with both parties after also receiving a complaint regarding the referee.

Ferguson says that he does not believe a referee would "stoop" to making racist or offensive remarks, and says that he has never had a player make a complaint to him about a referee swearing.

"There's no way a referee would stoop to that [racist or offensive remarks]. I'm convinced about that," he said.

"I think the modern game - if we see the game of 25 years ago - has completely changed. I played myself, and I know the banter goes on between referees and players is completely different from today. I've never had a player come to me in the last 15 years and say a referee has sworn at him in a game, ever. So, that's where I stand. I don't believe it."Follow GOAL.COM on